Pellet injector



June 26, 1956 G. M. HICKEY PELLET INJECTOR Filed Sept. 18, 1953 1-7 2..... r.. IIIIII-IIIIIII- WW W- BY Ema W ATTORNEYJ United States Patent PELLET INJECTOR Application September 18, 1953, Serial No. 380,961

3 Claims. (Cl. 128-221) This invention relates to a device for't he hypodermic injection of pellets. i

The invention is. intended for use more particularly on domestic animals although it is of'course' usable on humans. e i

In many instances in the care of.dom'estic animals it is desirable to be able to inject materials such as medicines, hormones and the like in solid form into the animal. This usually is done by merely puncturing the skin of the animal and depositing the material thereunder in the form of a tablet or pellet. Since the pellets or tablets generally are of substantial size 6. g. up to A2 inch or even more in diameter it is necessary to make a hole in the skin of such size that the pellet may be inserted. This can be done of course by cutting a small slit in the skin but this gives rise to a need to close the cut to prevent bleeding and infection and loss of the pellet. A better method is to penetrate the skin by means of a trocar or needle which makes only a small hole and stretches the edges thereof to a size large enough to permit the insertion of the pellet. Then when the needle is withdrawn the hole closes due to elasticity of the skin making it unnecessary to perform any act for closing the hole to prevent bleeding or infection or loss of the pellet.

A more particular object of my invention therefore is to provide a needle or trocar for the penetration of the skin and for depositing a pellet under the skin.

In providing a needle of the large size required for the injection of a pellet the cutting or coring actions of the needle are important considerations. The conventional hypodermic needle point, consisting of a straight tube cut oif at an oblique angle, both cuts and cores but this action in the case of the small conventional hypodermic needles used for the injection of liquids and even in the case of the larger needles used for Withdrawing blood is not critical although much has been done in an efiort to minimize it. However, in the case of a trocar of a size suitable for the injection of pellets coring and cutting action is an important consideration.

A further object of my invention therefore is to provide a needle point which practically eliminates coring and cutting even in large size, e. g. inch diameter.

The invention is illustrated in the accompanying drawings in which Fig. 1 is an exploded elevational view of the complete injection device,

Fig. 2 is an axial section with parts appearing in elevation of injection device including the needle or trocar and the mechanism for pushing the pellet out of the needle which serves also as a handle for the needle, said mechanism corresponding in structure and function with the syringe used with a hypodermic needle for the injection of liquids, and

Fig. 3 is a section on the line 3-3 of Fig. 1.

Referring to the drawings, 1 is the body or barrel of the syringe and consists of the finger grip portion 2, the integral chuck portion 3 and the integral sleeve guide portion 4.

ice

An axial cylindrical opening extends through the portions 2, 3 and 4. Within the portion 3 this opening is of a size adapted to snugly receive the end of the needle 5. Within the portion 2 the opening is of smaller diameter and adapted to provide a guide for the sliding movement of the plunger shaft 6. The difference in diameter of the opening in the portions 2 and 3 forms the shoulder 7 which serves as a stop or seat for the end of the needle. The diameter of the opening in the portion 4 is about equal to that of the opening in the portion 3 and the difference in diameter of the opening in the portions 2 and 4 provides another shoulders which serves as a stop or seat for one end of the cylindrical spring 9. The portion 3 is tapered and slitted lengthwise and screw-threaded to receive the screw-threaded nut 10 for securing the needle 5 to the body 1. The portion 4 is provided With slits 11 in which the ears 12 on the shaft 6 move when the shaft is moved forwardly to eject a pellet and retracted to a position inwhich the needle may be charged with a new pellet. The slits 11 may be of such length that their inner ends serve as stops for the ears 12 when the plunger 6 has reached the end of its stroke and its end has moved a sufficient distance into the pointed end of the needle to eject the pellet. Or the slits may be of greater depth and the button 13 on the end of the plunger may stop the forward movement of the plunger by engaging the nut 14. The portion 4 is screw-threaded to receive the nut 14 which latter serves as a stop for the cars 12 to retain th plunger 6 in position in the body 1. The spring 9 is tensioned to return the plunger 6 to its starting or retracted position as shown in Fig. 2 after it has been pushed forward to eject a pellet. The threaded end of the portion 4 is provided with notches 15 extending laterally from the slits 11, which notches 15 are adapted to receive the ears 12 and hold the plunger 6 in its retracted position. Thus the plunger may be turned with respect to the body 1 to position the ears 12 in the notches 15 and hold the plunger in its retracted position while the needle is being inserted. Then by a reverse rotation of the plunger the ears 12 are positioned to slide in the slits 11 and the plunger may be pushed forward to eject apellet.

The needle 5 consists of the cylindrical tubular portion 16 and the conical portion 17. The opening 18 through which the pellet is ejected starts in the cylindrical portion at a substantial distance from the base of the cone and extends forwardly toward but does not extend to the point of the needle as in the conventional hypodermic needle. Thus the penetrating point of the needle is not a cutting edge formed by the intersection of the cylindrical outer surface of the needle cannula and a plane extending obliquely to the axis of the cannula but is conical in shape. The opening is such as might be formed by the intersection of a cylindrical surface with the conical and cylindrical surfaces of the needle, the axis of the cylinder extending at right angles to the axis of the cannula and being of such a size that it intersects the cylindrical surface at a substantial distance from the base of the cone and the conical tip at a substantial distance from the apex of the cone and extends into the cone to about the axis thereof at a point adjacent the base of the cone.

It will be appreciated that considerable variation in the shape, size and location of the opening is permissible within the scope of my invention. One requirement however is that .it shall not extend all the way to the tip of the needle. A small portion of the conical surface adjacent the tip must be left. At the rear end however the opening may extend exactly to the base of the cone or it may terminate short of the base or extend beyond the base into the cylindrical surface. Also the opening, that is, the imaginary surface connecting the opposite edges of V the cone.

the opening, may extend inwardly to the ax is or beyond the axis or short of the axis. a

I have found needles of the shape illustrated to give excellent results. In the needle illustrated the conical portion is about 71 inch long, the base of the cone is about inch in diameter, the conical tip is about inch long and the opening extendsfrom the conical tip to a point about 3 of an inch to the rear of the base and the edges of the opening are on an arc of a cylindrical surface which intersects the axis of the cone at about the'base of The conical and cylindrical surfaces of the conical and cylindrical portions of the needle preferably terminates at a substantial distance from the apex of said tip portion, the maximum dimension of said opening measured in the direction perpendicular to the longitudinal axis of the needle being equal to the internal diameter of said cylindrical body portion.

2. A hypodermic needle as defined in'claim 1 in which the opening extends longitudinally from a point in r the cylindrical portion at a substantial distance from said merge into each other without a sharp angle "at the junction,

The syringe is adapted to inject pellets of any suitable shape such as spherical or cylindrical. i have found that needles of the shape described penetrate the skin readily and with very little damage by cutting or tearing, thatthe pellet readily may be inserted into the needle and that the pellet readily is discharged from the needle under the skin. 7

I am aware that a variety of minor changes in the 7 details of the structure disclosed readily may be made by one skilled in the art without departing from the scope of my invention as'deiined in the appended claims.

I claim:

conical portion to a point at a substantial distance from the apex of the tip'portion.

3. A hypodermic needle as defined in claim 2 in which the opening has the shape of an opening formed by the intersection of a cylindrical surface the axis of which is perpendicular to the axis of the needle and the diameter of which is such-that it intersects the needle at a point on the cylindrical-portion at a substantial distance from the base of the conical'portion, a point on the conical portion at a'substantial distance from the apex and a point 1. A hypodermic needle comprising a hollow cylindrica'l body portion and an integral hollow conical portion having'a single'ope'ning in the side wall thereof which on the axis of the cone adjacent the base thereof.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain June 14, 1950 

